Hives Symptoms: What They Look Like

Hives, known in the medical world as urticaria, are your skin’s reaction to histamine (a chemical released by the body’s immune system in response to an allergen) and other inflammatory signals being released into your bloodstream. (1)

RELATED: What Is Histamine?

You likely know hives for the way they appear on your skin: They’re red, swollen welts that can sometimes be accompanied by itchiness or pain. There are a variety of possible causes for hives (or reasons that histamine and other chemicals get released by the body in the first place). They could be the result of allergies in response to foods, medication, or an infection, or they could be from another trigger, like exercise, heat, stress, or alcohol. (2,3)

Red bumps on the skin can seem like a somewhat generic description. Couldn’t that indicate a number of possible skin issues? How can you know if it’s hives you’re experiencing and not something else? Here’s what to know about hives and their unique symptoms.

“Hives are characterized by red or pale-colored welts on the skin, which typically come and go throughout the day,” says Sourab Choudhury, DO, a dermatologist and the chief medical officer at the Dermatology Specialists, a private dermatology practice in New York City. “Sometimes they itch, burn, or sting.”

Usually the welts will be surrounded by clear edges. They may look similar to bug bites, but hives generally will appear and disappear more quickly. They may itch, sometimes severely, and they’re not always the same size or shape. They may be as small as the tip of a pen or as large as a dinner plate. (4) When you press the center of a hive bump on the skin, it likely will turn from red to white, which is known as blanching. (2,3)

Hives may appear on the body grouped together and take over a large area of the skin, or as a couple of individual welts that show up here and there. (4) They can appear anywhere on the body, though some people get them in the same spot over and over again (usually as a result of a specific trigger). (4)

Generally, you’ll know you have hives simply by seeing the hives themselves. If you experience other symptoms, such as swelling in the eyes, lips, or inside of the throat, or if you have trouble breathing, you should call 911 or see a doctor immediately, says Sapna Palep, MD, a dermatologist at Spring Street Dermatology in New York City. These symptoms indicate you may be experiencing a serious allergic reaction called anaphylaxis. (5)

“To the untrained eye, hives can have a similar appearance to other common skin conditions,” Dr. Choudhury says. He says one way to tell the difference is by how quickly the welts clear up.

“Hives will usually have an area of skin that welts up, goes away in a few hours, and then reappears somewhere else,” he says. Other skin issues that are often mistaken for hives tend to last for more than one day in the same location, he explains.

Also, check out the welts up close. “If the welts are filled with clear fluid, pus, or are brownish in color, it is likely not hives,” says Dr. Palep.

Hives are often mistaken for the following skin issues:

• Angioedema is swelling of tissue deep in the skin. It’s usually caused by an allergic reaction, certain medicines, or a genetic disposition. Generally, angioedema is accompanied by swollen lips, eyelids, hands, throat, or feet, trouble breathing, and cramps. (3)
• Eczema (atopic dermatitis) is common among children but can affect adults, too. Severe itchiness (especially at night), fluid-filled bumps, and red to brownish-gray patches indicate eczema rather than hives. (6)
• Bug bites may resemble hives in looks, but hives tend to behave differently. Hives may change shape and move around the body, whereas a bug bite stays in the same place. (3)
• Rosacea usually appears as redness on the face where swollen blood vessels become visible. It’s most common among middle-aged women with fair skin. The bumps look like acne and may contain pus, which hives generally do not. (7)
• Heat rash (also known as prickly heat or miliaria), as the name suggests, typically appears in hot and humid weather. Like hives, heat rash will appear as red bumps on the skin, though heat rash among adults generally occurs in areas where sweat gets trapped, such as in the armpit area, elbow creases, and the groin. (8)
• Contact dermatitis is a skin reaction that results from direct contact with something you’re allergic to, such as soap, jewelry, or a plant. The rash may be accompanied by blisters and typically lasts between two and four weeks, whereas hives will come and go within 24 hours. (9)

As mentioned, acute hives will usually disappear within 24 hours. It might seem like longer, though, because new hives may appear when old ones go away. In total, you could be dealing with hives for six weeks. (4)

If you have chronic hives, however, the hives will last for longer than six weeks. (4) They may be recurring and may come up at seemingly random times over the course of many months or years. (2)

Acute hives (the ones that clear up within six weeks or less) can be straightforward and may not require medical attention. But sometimes hives do warrant a visit to the doctor — or the emergency room in severe cases. It’s a good idea to visit your primary care doctor if you notice the hives continuing to appear over the course of several days or if you experience severe symptoms and discomfort. (2) If the rash tends to pop up on and off again over a stretch of time, you may want to visit an allergist. They will likely run special tests to identify possible triggers that are causing the breakout. (3)

Be on the lookout for more threatening symptoms, too. If you suspect angioedema (mentioned above), you should visit the emergency room immediately. (4) You should also seek emergency care if the hives are associated with an allergic reaction and include other symptoms such as dizziness; swollen lips, eyes, and tongue; or anything that makes it hard to breathe. (2) A good rule of thumb is that if you’re having trouble breathing, go to the emergency room or call 911, Choudhury says.